Why should flammable gas be extinguished with dry powder fire extinguishers?
The fire is the core component of dry powder fire extinguishing agent, can play the role of the fire extinguishing material mainly includes: K2CO3, KHCO3, NaCl, KCl, (NH4) 2SO4, NH4HSO4, NaHCO3, K4Fe (CN) 6 - 3H2O and Na2CO3, currently has the production of products: ammonium phosphate, sodium bicarbonate, sodium chloride, extinguishing agent. Each fire particles have a particle size less than the upper limit, the critical size of particles are on fire extinguishing effect is greater than the critical diameter of the particle extinguishing efficiency decreases sharply, but its momentum, through the air force on the aerodynamics of small particles, forcing small particles followed toward the flame center, but not to the flame it was blowing hot air flow, reduce the efficiency of fire extinguishing. The particle size of commonly used dry powder extinguishing agent is between 10~75 and M. The dispersion of this particle is poor and the specific surface area is relatively small.
One is the volatile decomposition of the inorganic salts in the dry powder, which is chemically inhibited and negatively catalyzed by free radicals or active groups produced in the combustion process, so that the combustion chain reaction is interrupted and the fire is put out;
The ordinary dry powder extinguishing agent is mainly composed of active components, fire extinguishing composition, inert filler composed of hydrophobic, hydrophobic and hydrophobic silicone oil is the main component of white carbon black, inert filler variety, mainly anti vibration, agglomeration, improve the motion performance of dry powder, dry powder and silicone oil catalytic polymerization to improve the tolerance function and foam fire extinguishing agent. This kind of ordinary dry powder extinguishing agent has been widely used at home and abroad.
The two is that the powder of the dry powder falls outside the combustible surface, produces chemical reaction, and forms a glass covered layer under the action of high temperature, thus isolating oxygen and smothering the fire. There is also partial dilution of oxygen and cooling action.
